1. Field of the Invention
The present invention relates to an infrared solid-state image pickup apparatus provided with a semiconductor device such as a diode as a thermosensitive device and a production method thereof.
2. Description of the Related Art
In a conventional infrared solid-state image pickup apparatus, image information has been obtained by using a PN junction diode formed in a silicon layer as a thermosensitive device and using an output signal of the PN junction diode. Further, an impurity distribution inside a P type semiconductor layer of the PN junction diode and an impurity distribution inside an N type semiconductor layer have each been performed in an even manner (for example, refer to M. Ueno et al., “Non-Cooling Infrared Image Sensor Having 320×240 Pixels using SOI substrate”, Technical Report at Video Information Media Symposium, Vol. 24, No. 17, pp. 53 to 58 (Feb. 25, 2000)).
In a PN junction diode in a conventional infrared solid-state image pickup apparatus, a semiconductor layer of the PN junction diode has been encompassed by a separation oxide film therearound for device separation, an insulating film thereon for protection of the PN junction diode and the like. In an interface between these separation oxide film and the like and the semiconductor layer of the PN junction diode, an interface trap is present and, then, electrically conductive carriers are generate-recombined, to thereby generate a noise. For this account, there has been a problem in that an SN ratio of an output of the PN junction diode, consequently, an SN ratio of an output of the infrared solid-state image pickup apparatus is decreased.